Method and apparatus for the melting of metals



J1me 9- H. E, BURKE ET AL 2,163,503

METHOD AND APPARATUS FOR THE MELTING OF METALS Filed Sept. 10, 1958 M 2 l8 I I i 3 A 3 i 1 g. 2. f 1 g 5.

a4 8 l2 8 y M/ '2 ML, m7 1 E 38 \2 V5 j -30 f ao s *26 JQZZZLIIA ZA gwuvm bom HUGH E. BURKE CHRISTOPHER J. FREY REID B. GRAY Patented June 20, 1939 LIETHQD AND APPARATUS FOR THE DELTING OF METALS Hugh E. Burke and Christopher J. Frey, Bal

more, and Reid B. Gray, Dundalk, Md., ass mors to The Glen L: Martin Company Application September 10, 1938, Serial No. 229,310

6 Claims.

' The present invention relates to methods and apparatus for the melting of metals, and particularly to the melting of zinc. Q.

In the past it has been the practice to melt zinc by placing it in a metal pot and heating the pot. Although various efforts have been made to distribute the heat over the pot, nevertheless the heat has always been concentrated. The result of this concentration of heat is that the zinc which is in contact with the metal pot at the points of highest concentration of heat alloys with the metal of the pot. This results in the introduction of impurities into the zinc, and in the gradual corrosion of the pot, which must be periodically replaced.

The object of the present invention is to provide a means and method of melting zinc which substantially entirely prevents the alloying of the zinc with the metal of the pot, thereby preventing the contamination of the zinc and the corrosion of the pot.

More particularly, the invention contemplates the application of uniform heat at all points on the outside of the pot by a novel mode of procedure.

Especially, the invention contemplates the provision around the melting pot of a mass of lead or other metal or metallic alloy having a lower melting point than the zinc, which transfers heat from the outside to the metal pot in which the zinc is to be melted.

Further objects and advantages of the invention will appear more fully from the following description, particularly when taken in conjunction with the accompanying drawing, which forms a part thereof.-

In the drawing:

Fig. 1 is a cross section through a zinc melting device made according to the invention.

Fig. 2 and Fig: 3 are crcss sections on the lines 2--2 and 33 respectively of Fig. l.

As shown in the drawing, the invention comprises a metal pot or container in which the zinc is to be melted. This container is provided with a suitable cover 4. The pot 2 has at its top outwardly extending flanges 6 adapted to support the pot. These flanges rest on the top of the side walls 8 of a casing which is completed by a bottom portion In. These walls are preferably formed of some'refractory material such as firebrick. The casing is covered on the outside by a sheet metal cover as at l2.

The bottom of the chamber formed within the casing constitutes a combustion or heating chamber I4, into which, for example, gas and air may (c1. est-s3) be introduced by pipes l6, so that the gas will burn within the chamber I4 and produce heat. Obviously, however, the invention is not limited to gas heat, and any other. satisfactory manner of producing heat within or supplying it to the 5 space ll may be used.

The pot 2'i s arranged within and spaced from a second and larger pot i6, the bottom of which forms the upper wall of the heating chamber I4. This pot II is also provided with outwardly exw tending flanges 20 at its upper edge, which underlie the flange 6 and'rest directly on the top of the wall 8. The flanges 6 and 20 may be secured to each other by bolts 22 passing through both flanges and threadedly engaging in an angle iron 15 24 arranged around the upper inside edge of the walls I.

The space between the pots 2 and i8 is substantially entirely fllled as at 26 with lead or any other suitable metal or alloy having a lower 20 melting point than the zinc. Preferably this metal is such that it does not vaporize at the melting point of zinc. There is also provided in the bottom of the pot 2 a layer 28 of lead or some other suitable metallic material.

In the walls 6 there are formed flues 30 which communicate at their lower ends with the heating chamber l4 and which extend upwardly along the outside of the pot l8, and then emerge to the atmosphere through horizontal passages 32. These permit the escape of hot gases from the heating chamber ll.

The outer pot I8 is preferably supported by angle members 34 which rest on the base plate 36 beneath the bottom wall III of the casing and 35 are covered by refractory material as at 38 to prevent corrosion of the metal of the supports 34.

The device just described is used and operates in the following manner:

The inside of the pot 2 is filled with zinc in 40 lumps or otherwise. Gas and air are introduced through the pipe i6 and are ignited in the chamber M. The heat of combustion heats the pot I8 and thereby the lead 26. The lead melts, and the molten lead transmits the heat to the 45 walls of the inner pot 2. The lead distributes the heat evenly over the whole wall of the inner pot, and thus prevents concentration of heat in any one point or any group of points. Therefore the zinc is melted by a uniform applica- 50 tion of heat to all parts of the pot, and no part of the pot is raised to such a temperature that the zinc at that point will alloy with the metal of the pot. The zinc thus obtained is therefore quite pure, and free from contamination with 55 2 2,168,508 metal, and at the same time the Dot 2 is not corroded and can be used for much longer peri- Ods of time without replacement. Since such replacement requires not only the cost of a new not but also the labor of dismantling the whole apparatus, it is evident that a considerable saving is effected.

-When after long use a new pot is required, all

that is necessary is to remove the screws 22,-

lift out the old pot and place a new one in position.

While we have described herein one embodiment of our ingention, we wish it to be understood that we do not intend to limit ourselves thereby except within the scope of the appended claims.

We claim:

1. A method or melting a metal in a pot, which comprises melting on the outside of said pot and in the bottom of said pot a metallic material having a lower melting point than the metal to be melted, supplying substantially all the heat to said metallic material on the outside of said pot from the bottom, and transferring heat from such molten metallic material on the outside of said pot to the metal to be melted through the pot.

2. A method of melting zinc in a metal pot which comprises melting on the outside of said pot and at the bottom of said pot a metallic material having a lower melting point than the zinc to be melted, supplying substantially all the heat to said metallic material on the outside of said pet from the bottom, and transferring heat from such molten metallic material on the outside 01' said pot to the zinc through the pot.

3. An apparatus for melting metal comprising an outer pot, an inner pot within said outer pot and having its bottom and side walls spaced from those of the outer pot, a metal having a lower melting point than the metal to be melted substantially filling the space between the inner and outer pots, a layer 01' metal having a lower melting point than the metal to be melted on the bottom or the inner pot, and means to supply substantially all the heat to the bottom of the outer pot.

4. An apparatus for melting metal comprising a refractory casing, an outer pot located within said casing and forming therewith a heating chamber, the side walls of said pot engaging the casing through the greater portion of their area, an inner pot within said outer pot and having its bottom and side walls spaced from those of the outer pot, a metal having a lower melting point than the metal to be melted substantially filling the space between the inner and outer Pots, and a layer of metal having a lower melting point than the metal to be'-melted on the bottom of the inner pot- 5. In a device as claimed in claim 4, upwardly extending flues connected with said heating chamber to conduct of! hot gases therefrom.

6. In a device as claimed in claim 4, upwardly extending flues connected with said heating chamber to conduct oil hot gases therefrom, said flues passing on the outside of the outer pot.

HUGH E. BURKE. CHRISTOPHER J. FREY. REID B. GRAY. 

